Messenger strand mounted pico-cell radio

ABSTRACT

A messenger strand mounted low-power pico-cell radio, having its own environmentally controlled box, mounted on utility messenger strands, connects to the cable using the Internet protocol (IP) for back-haul, and has in-band monitor and control capability. These pico-cell radios also receive power through the same cable connection. The configuration control and monitoring is by independent discretely-managed internal mechanisms that can be remotely addressed. These internal mechanisms include the modem for backhaul, wireless radio transceiver(s), and the system management device for operation, administration, maintenance, and control. Such pico-cell radios help to provide wireless connectivity and coverage efficiently by reducing dark spots in wireless coverage. Distributing these radios in reasonable, close proximity enables wireless coverage in difficult terrains, where current high power systems fail. The radios disclosed herein eliminate the need and cost for additional power lines and IP connection lines, and are therefore easy to install and maintain.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to wireless communication systems. In particular,the invention relates to pico-cell radios mounted on utility messengerstrands.

2. Discussion of the Prior Art

Currently, cell phone connections are made using high-power radios thatare installed on radio towers and that are back-hauled through highbandwidth connections, typically T1 lines, to the mobile carriers. Theseradio cells are powered through external power supplies from main powerlines.

A cell based wireless communication system that is currently implementedfor cell phone communication consists of at least a mobile station and abase station connected to multiple stationary radios and forward andreverse links between them. The geographical area to be covered bywireless communication is divided into various cells. The radioequipment, i.e. a base-station transceiver subsystem (BTS), is installedin each such cell. The BTS consists of five major blocks a radiofrequency (RF) front-end, transceivers, modem processors, a controller,and a power supply. The RF front-end and transceiver form a stationaryradio unit (RU) within the BTS. The rest of the blocks typically formthe main unit (MU) of the BTS. The BTS also includes antennas. Theantennas can be omni-directional, or directional if the cell is dividedinto sectors. Each sector may have its own transmitting and receivingantennas. Two antennas per sector are required for diversity reception,thereby minimizing the effects of fading and multipath. In cells wherethe communication capacity is high, more than one RF carrier signal canbe transmitted. This again increases the number of antennas. In older,integrated BTS systems, the BTS cabinet is located on the ground or in ahousing near a mounting structure, such as a pole or a tower. Theantennas are mounted on top of the mounting structure. The BTS isconnected to the antenna by a coaxial cable that is typically about 50to 200 feet long, depending on the height of the tower and the locationof BTS on ground. Due to the cable length, a significant amount of poweris lost between the BTS and the antenna. To reduce the power loss,thicker power cables are used, typically ¾″ to 1″ in diameter, whichincreases cost. Even then, at the required frequency of transmission,the power loss is considerable. This leads to degradation of receiversensitivity and a reduction in the final transmitted power. Themaintenance of these BTS is done by having the maintenance personaldrive out to the location (truck roll) to check and repair of any faultsat the site. These truck rolls are very expensive.

FIG. 1 shows a prior art implementation of a more modern, cell-basedcommunication system base station 100. In this typical system, the RU110 is removed from the MU 105 and located closer to the antenna 120 toreduce the problem of power loss. The MU 105 is retained at the bottomof the mounting structure 130. Before up-conversion to RF, the signal iscarried by the cable 140 from MU 105 to RU 110. Because the signal is alow frequency signal, the loss in the cable is minimized. On the receiveside, the cable also carries a low frequency signal because the RF isconverted to a low frequency in the RU 110 and passed to the MU 105 foronward transmission. The high power amplifier can be replaced by a lowerpower amplifier because the cable loss is reduced. This helps reduce thesize and weight of the RU 110. The size of the MU 105 is also reducedbecause the radio unit is removed from it. Many RUs 110 can be connectedto a single MU 105, which then acts as a main base station. One or moreantennas 120 can be connected to each RU 110, depending upon therequirements. The RUs 110 can be made to operate in differentfrequencies, different power levels, and different protocols.

A direct current (DC) power line 170 supplies power to the RU 110 bymeans of external power supplies 150, converted from main power lines160. These power lines 160, from a main power source, must be installedat the site for the power to be supplied to the external power supplies150. This increases the cost of establishing the cell based system 100.

Recent advances in wireless implementation have included messengerstrand mounted modems for static connectivity to homes, etc. Thesededicated systems are used to connect a receiver to a transmitter,typically using a high speed bidirectional antenna. This helps set upback haul stations for providing high speed links to homes, etc., asdescribed in the Smith U.S. Pat. No. 7,162,234, by using pole mountedseparate antennas. The capability to act as a base station with theability to transfer connection of portable/mobile wireless devicesbetween adjacent strand mounted modems as the mobile wireless devicecustomer moves from coverage location of one modem to another has notbeen thought of. Such a system will be invaluable if implemented toprovide the coverage in inaccessible areas and hilly regions, wherewireless dark areas exist due to the inability of the cellular wirelesstowers to provide the necessary coverage.

SUMMARY OF THE INVENTION

A self-contained remotely-managed, outdoor, aerial messaging, strandmounted radio transceiver system serving mobile wireless client devicesis disclosed, in which one or more antennas are attached to utilitymessenger strands. Such system is back-hauled to the mobile operatorswitching facilities using internet protocol (IP) through coaxial cable,twisted pair(s), fiber optics, or wireless, and receives its powerthrough pre-existing coaxial cable or twisted pair power distributioninfrastructure. The system has capability for remotely or locallymanaging all of its components. The remote managed solution anddeployment methodology applies wireless connectivity efficiently whenattached to an aerial messaging strand to enable mobile wireless clientdevices. One or multiple systems, independently backhauled, distributedin proximity to one another, provide increased user capacity andwireless coverage in difficult terrains, where current high powersystems fail to meet the requirements of quality, coverage and cost. Theradios disclosed herein eliminate the need and cost for additional powerlines and IP connection lines, and are also easy to install andmaintain.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prior art cell-based communication system,

FIG. 2 is a functional block diagram showing a messenger strand mountedradio (MSMR) for use as a pico BTS according to the invention;

FIG. 3 is a block diagram showing the MSMR consisting of a radiotransceiver, a cable modem with power supply and remote, in-bandmanagement according to the invention; and

FIG. 4 is a block diagram showing a system with the MSMR used as picoBTS according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Currently, cell phone connections are made through high-power radiosthat are installed on radio towers, and that are back-hauled throughhigh bandwidth connections, typically T1 lines, to the mobile carriers.These radio cells are powered through external power supplies from mainpower lines.

A self-contained, remotely-managed, outdoor, aerial-strand-mounted radiotransceiver system, is disclosed. Such system was used to serve mobilewireless client devices. Such system has antenna(s) attached toutility-messenger strands. The system is back-hauled to the mobileoperator switching facilities through coaxial cable, twisted pair(s),fiber optics, or wireless and receives its power through pre-existingcoaxial cable or twisted pair power distribution infrastructure. Suchsystem has used to serve mobile wireless client devices. The system iscomprised of interdependent and discretely-managed internal mechanismsaddressable by multiple parties. These remotely managed mechanisms,without limitation, include:

-   -   (1) the modem for backhaul;    -   (2) the wireless radio transceiver(s);    -   (3) the independent system management device for        operations-administration and maintenance of the system; and    -   (4) the support/control/monitoring resources. This        remote-managed radio solution and deployment methodology helps        to provide wireless connectivity much more efficiently, as well        as to provide better signal coverage and/or higher user        capacity, when attached to aerial messenger strand to serve,        facilitate, or enable mobile wireless client devices. Having one        or more of these radio systems, each with independent backhaul,        placed as needed or distributed in proximity to one another,        enables wireless coverage and increased capacity where high        powered radio systems may fail due to a variety of reasons        including, but not limited to, cost, timeline, environment,        permissibility, and/or spectral limitations.

A messenger strand mounted, low-power radio, i.e. a low-power radio thatis mounted on messenger strands, that connects to the cable using theInternet protocol (IP) for back-haul needs, and that receives its powerthrough the same cable connection, is disclosed. Such radio helps toprovide wireless connectivity and coverage much more efficiently byreducing dark spots in wireless coverage. The radios used in theinvention are pico-cell radios that are placed at aerial cablelocations, and that are attached to the messenger strand. Distributingthese radios in reasonable, close proximity enables wireless coverage indifficult terrain, where current high power systems fail to meet therequirements of quality, coverage and cost. The radios disclosed hereineliminate the need and cost for additional power lines and IP connectionlines, and are therefore easy to install.

The disclosed invention is a messenger strand mounted radio (MSMR)comprising outdoor equipment which houses wireless radios. The MSMR is asmall, self contained unit/system that clamps to, and draws power andtransmission from, an overhead cable plant, usually a cable televisioncable.

The MSMR is used in an outdoor environment to fill-in targeted gaps inthe network, where either coverage or capacity enhancement are required.The MSMR solution could be used in areas where it is otherwise costprohibitive to provide targeted dark areas, or impossible to clearzoning in tougher jurisdictions; such as busy intersections, areas withhills, canyon and mountain roads, schools, and very RF restrictiveneighborhoods.

The MSMR seamlessly interfaces with the network of a cable operator, ora Multi-Service Operator (MSO), thus extending the reach of cableoperator's hybrid fiber and coax network using wireless technologies.The equipment is housed in a MSMR box which protects the components ofthe MSMR from environmental impact. The housing of the components alsoenables easy, secure mounting of the MSMR to the messenger strand. TheMSMR is unique in that it is placed on the coaxial aerial strand, whichis part of the outdoor cable plant. Placing the MSMR on the messengerstrand at, typically, a 20-23 feet elevation provides good height overterrain for radio coverage with low power radios. The aerial cable plantalso provides easy access to input power and data over cable serviceinterface specifications (DOCSIS) data backhaul.

FIG. 2 is a block diagram representation of an exemplary andnon-limiting MSMR 200, which can be used as a pico base-stationtransceiver subsystem (BTS), within its environmental protection housingbox 290. The MSMR 200 comprises a radio RF front-end, including atransceiver 250 (radio), antenna 120, monitoring module 260, cable modem270, coupler/splitter 280, and power supply 290. The exemplary radio 250used in this embodiment is a pico-cell radio which is able to support IPover Ethernet backhaul, and which is small enough and light enough to besupported on the messenger strand. It is also a low-power radio, suchthat the power needed for operation is provided through the cable 201.

Although in the example shown in FIG. 2 the choice of radio 250 is acellular BTS radio, typically referred to as a pico-cell radio, this isnot limiting, and other types of radios may be used without departingfrom the spirit of the disclosed invention. Therefore, not only cellularBTS radios 250 may be used, but also WiFi, repeaters, and WiMAX radios,depending on the application. The radios 250 can also be employed inpoint-to-point, point-to-multipoint, or mesh arrangements. The MSMR 200is capable of being configured to transmit and receive in any one of thedifferent cellular protocols. This configuration can be done remotelythrough the cable connection or locally.

The MSMR 200 uses a standard DOCSIS cable modem 270. The cable modem270, the monitoring module 260, and the radio 250 are IP addressable.This enables the in-band monitoring and control of the cable strandmounted radio 200 through the IP network and monitoring module 260. Thecable modem 270 interfaces with a coupler/splitter 280 to connect to theavailable cable 201 for back haul access. It interfaces with themonitoring module 260 through a standard Ethernet cable 210, typicallyCat5. Similarly, the monitoring module 260 interfaces with the radio250, typically via a Cat5 Ethernet cable 210. The power for the MSMR 200is derived from the quasi-square wave alternate current (AC) availablefrom the coaxial cable plant through the coupler/splitter 280. This ACpower is supplied to the power supply unit 220 to generate the needed DCsupplies to power the MSMR. The MSMR 200 is connected to the aerialcable, typically via a standard F-connector tap, at the coupler/splitter280. The housing box 290 of the MSMR 200 is suspended from the cablestrand using suitable means for attachment. One such attachment means isdisclosed in U.S. patent application Ser. No. 12/046,414, Cable StrandBracket, attorney docket no. AMBE0002, which is assigned to a commonassignee, and which is incorporated herein by this reference thereto forall that it contains.

FIG. 3 is a schematic diagram that shows an exemplary and non-limitingMSMR 200. The cable brings power and data into the cable modem and powerunit 350. The power input from the cable is separated from the datainput in the power section of the cable modem and power unit 350. Theextracted AC power is fed into the DC power supply unit 380 whichoutputs a regulated DC output. Further DC voltages are typicallygenerated from this DC output supply using DC-DC converters 310 as maybe necessary. The typical power input at the input from the cable is a35-90V quasi-square wave. The power supply unit 380, typically convertsthis square wave AC power to 48V DC and, through a DC-to-DC converter310, to 12V DC or other needed values to power the circuit components ofthe MSMR 200.

FIG. 3 also shows the system with its remote, in-band managementcapability using the monitoring and control module 360. To overcome theproblems caused by installing the MSMR system high above the ground inan outdoor environment with dynamic address changes and limited accessand visibility for configuration, repair and maintenance, a systemmanagement capability using a secure server 361 is included as part ofthe monitoring and control module 360. The data stream from the cablemodem and power unit 350 is fed to the monitoring and control module 360through, for example, a 10/100 Base-T LAN connection. The environmentalcontrol is handled by the secure server 361 that is part of themonitoring and control module 360. The secure server 361 is used toprovide effective monitor and control of the environmental conditions ofthe MSMR 200 continuously. The monitoring and control module 360 has atemperature and humidity measuring unit and a thermostat 390 that isconnected to it to provide environmental control for the housing box290. Other necessary sensors and actuators may also be connected to it.The environmental control capability built into the MSMR 200 enable itto operate in an outdoor environment as necessary. The monitoring andcontrol module 360 has complete in line capabilities, using the secureserver 361 for debugging, repair, measurement, calibration, andconfiguration to service the MSMR 200. Optionally, the monitoring andcontrol module 360 can also have an external connection port 365 thatallows on-site local debugging, repair, measurement, calibration, andconfiguration facilities to enable local servicing of the MSMR 200.

The secure server 361 enables the remote Network Operation Center (NOC)to remotely power cycle the radio transceiver(s) 250, the cable modem350, or the secure server 361 itself, individually or collectively, inthe event of a failure. To allow massive deployment, the secure server361 adapts to addressing dynamically in the event of an address change.The secure server 361 also supports a dynamic IP/NOC addressable—viaDynamic Domain Name Service (DynDNS) or report-home mechanism to easeits configuration and IP address management. Thus, whenever the IPassignment(s) of the MSMR change(s), the secure server 361 in the MSMRreports it to the one of two or more independent home configurationservers so that dynamic name to IP translation services can always beperformed correctly. The secure server 361 also has built in uptimecounters for verifying its own uptime, independently of the availabilityof other network functions, in the event of a backhaul failure.

The secure server 361, forming part of the monitoring and control module360, also enables efficient transfer and timely hand-off of the cellunits, or mobile wireless between adjacent MSMRs 200. The use of thesecure server 361 in the control and monitoring unit 360 enhances thequality of service and provides improved user experience during the handoff process between MSMRs 200 by making it seamless, transparent, andtimely.

The pico-cell radios 250 used are low power radios. They operate as picoBTS devices. The radio up-converts the quadrature amplitude modulation(QAM) signal to a 64 QAM or 256 QAM RF channel, and transmits it overthe air. The typical transmitted downstream frequency range is 91 to 857MHz and the typical channel bandwidth available is 6 MHz.

The radio 250 is connected to the transmitting and receiving antennas120. The RF coverage of the radio 250 is dependent on the type and gainof the antennas 120, the frequency of the signals, the RF output power,and the required signal-to-noise ratio (SNR). For a typical WiFi 802.11access point transmitting 1 Watt using a 5 dBi omni antenna, typicaloutdoor coverage radius is 500 to 700 feet of line-of-site. For indoorbuilding penetration, the typical radius is 300 feet. The MSMRs 200 havea limited capability to increase power, due to the limitation ofproviding the power supply through the cable. This necessitates theMSMRs 200 to be in reasonably close proximity to each other to providethe necessary coverage, even if power consumption increases.

Even though the disclosure typically covers the use of dual antennas forthe typical application, this is not to be considered limiting, as asingle antenna can be used for both transmission and reception. This isdone by coupling the antenna to the transceiver using either a duplexeror a diplexer as is done in other similar communication applications.

FIG. 4 shows a communication system 400 in which the MSMR 200 is used.The MSMR 200, in its housing box 290, is suspended from the cable strand401. The cable 201 is tapped 402 for power and data, and a connection403 is made to the cable modem 350 in the housing box 290. This connectsthe MSMR 200 to the cable for backhaul through the cable. A group ofpico BTS units in the form of the MSMRs 200 connect on the cable strandto cover a region. They connect via the established backhaul to thecable modem termination systems (CMTS) 440. From there, they connectthrough a standard connection via internet 430, to the main BTS router420 and to the carrier central office equipment 410. FIG. 4 shows twoMSMRs 200 connected to the cable as a pico BTS. One SCMR 200(1) pico BTScommunicates with three mobile wireless units 461, 462, and 463, and asecond MSMR 200(2), as a second pico BTS, communicates with one mobilewireless unit 464. Typically, the local MSMR 200 used as pico BTS hasthe capability and intelligence built-in to route and connect the localtraffic, and only sends out-of-cell traffic for routing to the centralunit 410.

The typical housing box 290 is made of machined casting which iselectro-magnetic interference (EMI) and humidity sealed. No movingcomponents, such as fans and electromechanical switches, are used. Thisensures high reliability. This arrangement is possible due to thelow-power dissipation of the MSMR 200. The MSMR 200 is environmentallyhardened to meet the reliability requirements of standard outdoor cableplant equipment a typical cable strand mounted radio 200 is designedwith a form factor that fits the dimensions per GO-95 to ensure thatthere is no interference with other strands on the utility poles.

Installation of the MSMR 200 is very easy. The housing box 290, with thenecessary equipment inside, can be mounted on the aerial strand bytightening down the housing box 290 strand clamps. After mounting thehousing box 290, a power and data tap 402 is made to the cable plantnear the location of the housing box 290. A connection 403 is then madeto the cable modem 350 inside the housing box 390 from the tap 403 usinga short length of coaxial cable. Typical time for installation of theMSMR 200 is less than one hour using a bucket truck and standard cabletechnician tools.

Use of the MSMR 200 as a pico BTS has at least the following advantages:

-   -   1. The low power radios, distributed fairly close to each other,        provide more efficient wireless coverage by reducing coverage        dark spots in difficult terrain, where high power system do not        penetrate or are not efficient.    -   2. Lower cost of installation because the complete installation        can be typically handled in an hour or two.    -   3. Lower input in time and labor for configuration, maintenance        and repair as most of this is done on-line. This results in        lower cost of operation.    -   4. Better quality of service to users is ensured by use of the        optimized hand off procedure used.    -   5. The MSMRs are powered from the cable and, as such, do not        need special power connections to be drawn to each location        where installation is done.    -   6. The use of the cable for backhaul reduces the cost of pulling        cable to provide backhaul facility.    -   7. No new towers need to be established.    -   8. Low cost of system due to use of lower cost pico BTS.    -   9. Faults in the system have limited impact because load can be        taken over by nearby pico BTS.

Although the invention is described herein with reference to thepreferred embodiment, one skilled in the art will readily appreciatethat other applications may be substituted for those set forth hereinwithout departing from the spirit and scope of the present invention.Accordingly, the invention should only be limited by the Claims includedbelow.

1. A cable strand mounted radio (MSMR), comprising: a cable modemconnected to a cable strand through a coupler/splitter; said MSMRcomprising means for using said cable strand for backhaul capability; amonitoring module connected to said cable modem; said monitoring modulecomprising a secure modem, and environmental sensing and controlelements; a radio unit connected to said monitoring module; at least apair of antennas connected to said radio unit, a first antenna fortransmission and a second antenna for reception; and a power supply unitconnected to said cable strand through said coupler/splitter, said MSMRreceiving power from said power supply through said cable strand from acable plant; said MSMR comprising means for mounting it on said cablestrand and comprising a base transceiver station (BTS).
 2. The MSMR ofclaim 1, further comprising: a housing for enclosing all components ofsaid MSMR.
 3. The MSMR of claim 2, said means for mounting comprising:one or more clamps for attaching said housing box to said cable strand.4. The MSMR of claim 1, said radio unit comprising: a low-power radiounit.
 5. The MSMR of claim 1, said radio unit comprising: a pico-cellradio unit.
 6. The MSMR of claim 1, said MSMR comprising: a picobase-station transceiver subsystem (BTS).
 7. The MSMR of claim 1, saidmonitoring module comprising means for providing said MSMR with in-lineoperational capability for at least one of configuration, measurement,calibration debug, and repair.
 8. The MSMR of claim 1, said monitoringmodule comprising means for providing said MSMR with in-line control ofthe environment of said MSMR.
 9. The MSMR of claim 1, said monitoringmodule comprising means for providing local access of the MSMR for atleast one of measurement, calibration debug, and repair.
 10. A methodfor providing wireless coverage, comprising the steps of: connecting acable strand mounted radio (MSMR) to a cable strand for backhaulconnectivity; providing power to said MSMR via said cable strand;providing in band control of operation and environment of said MSMR; anddistributing multiple MSMRs in close proximity to each other to providefull coverage of a terrain.
 11. The method of claim 9, furthercomprising the step of: installing said multiple MSMRs to ensurewireless coverage in difficult terrain where high power systems areineffective.
 12. The method of claim 9, further comprising the step of:using said MSMR to eliminate at least one of dedicated power lines andInternet protocol (IP) connection lines.